Control of railway trains



June 10 1924. 1,497,416

w. J. UNDERWOOD CONTROL OF'RAILWAY TRAINS Filed Feb. 28 922 2 Sheets-Sheet. 1

Patented June 10, 1924.

STAES WALTER JOHN UNDEBWOQD, OF LONDON, ENGLAND.

CONTROL or nAiLwAY TRAINS.

Application filed February 28, 1922. Serial No. 539,834.

To all whom it may concern:

Be it known that I, lVAL'rnR JOHN UN- Dnnwoon, of London,'I lngla-nd, a subject of the King of Great Britain and Ireland, have invented certain new and useful Improve ments in and Relating to the Control of RailwayTrains, of which the following is a specification.

This invention relates to the control of railway trains and has for its object to pro vide an improved arrangement of apparatus for controlling the movement of railway trains and vehicles passing over the same track rails in opposite directions.

The term single track railways in the claims is to be understood as including the use of any one of the tracks of a multi-track railway for the passage of traflic thereover in both directions, whether regularly or only occasionally, throughout the whole length of the track, or only on certain sections.

In short, the object of the invention is to provide an improved arrangemento't electrical controlling apparatus of the foolproof type designed to control the movement or indication of any electrically controlled or operated track devices for governing the movements of the trains in such a manner that the movement of only one train at atime on to the single track is allowed and any conflicting train movement is positively disallowed without requiring any such safeguards as statl and ticket mechanism or any mechanical or electrical interlocking or slot devices. In all'cases no other interlock is necessary between the operating switches beyond thatconstituted by the apparatus itself, as hereinafter described.

The improved arrangement according to my invention comprises at each end of a single track section a separate electrically controlled track device, or set of devices oi any usual kind (trip, signal, switch points, or the like) normally set against the passage ofthe trains over the single track, a non mally open circuit foroperating each trafiicregulating device, said circuit comprising a line wire connecting both of the traflicregulatiug devices, and a separate manually operated circuit closer for each traffic-regulating device, each circuit closer being adapted to control the said circuit and having a normal position, in which it is completely disconnected from all parts of the circuit, and two movements therefrom in opposite directions, the'movement in one direction closing part of the operative circuit of the local traflic-regulating device, or set of devices, and the movement in the opposite direction closing part of the operative circuit of the other traflic-regulating device, or set of devices, the arrangement being such that only one traflicregulating device, or set of devices, at a time can be operated to allow one train to pass over the single track, and only by the positive and joint movements of both of the circuit closers, one in one direction, and the other in the relatively opposite or different direction.

In order that the invention may be clearly understood arrangements in accordance therewith will now be described as examples with reference to the accompanying drawings in which Fig. 1 is a diagram of circuits illustrating the application of the invention;

Fig. 2 is a modification of the arrangement shewn in Fig. 1;

Fig. 3 illustrates an electro-pneumatically operated trip device of a well known type which may be usedwith this invention, the trip being adapted to, close an electric switch (controlling a signal or the like circuit) on moving to its safety position and to open the switch on moving to its danger position.

While preferring train stopping devices as producing the desired result in emergencies and giving confidence to the drivers without in'ipairing their sense or danger, I do not intend to limit the scope of my, present invention to th control of such devices, as the invention can be utilized. equally well for the direct or indirect control of any or all. of the usual devices governing the movements of trains such as signals, points, lever locking devices. barrier gates, and others, provided only that the said devices are electrically controlled or operated. Hence where l have shown or described the use of my invention for controlling train stopping devices it is to be understood that the invention could he applied in a substantially similar manner for the control of any other kind oftraliio regulating devices, whether actuated power or .by hand.

By the use of the invention I prefer to completely dispense with the present stalf and ticket system of control and to control the trafiiogoverning devices directly by means of my invention. On the other hand the invention can be employed for the'op-- eration of a staff and ticket selecting mechanism, if desired.

Referring first to Fig. 3, an electropneumatically operated trip device is shown herein of a kind so well known that a minute description of the valve mechanism and other internalparts is considered unnecessary. The operating cylinder is shown at a to which compressed air is admitted by the electro-magnetic valve mechanism contained in the casing b when an electric current is supplied to the said mechanism by means of leads 0, (l connected to a controlling circuit, in the present case the line circuit. \Vhen the electrdmagnet of the valve mechanism is tie-energized the cylinder (4 is connected by the valve to atmosphere. The piston in the cylinder (0 is suitably connected to the rod 0 the free end of which is connected to a crank f on a shaft 9 supported in suitable bearings on the track to which shaft is fixed the trip arm h adapted to co-act with atrip lever or signalling device on a passing train.

In the tie-energized condition of the elec tro-magnetic valve the piston in the cylinder a and the connecting rod 0 are held in their normal position by the coil spring 2', which surrounds connecting rod (2 and abuts at one end against a fixed bracket j and at the other end against a collar secured on the rod 0. Thus the shaft y and trip arm h are held in the normal danger position shown by the action of the spring 2', the trip arm in this position engaging the trip lever on the train and causing the brakes to be applied, or a danger signal to be given in the cab of the engine.

A compressed air supply is connected to the casing 7) in such a manner that when the electromagnetic valve is energized by means of an electric current traversing the leads a, (Z the valve is thus moved to admit said compressed air into the cylinder a behind the piston therein,- the communication between the cylinder and atmosphere being simultaneously cut off. The piston is thus moved over to the other end of the cylinder a, compressing the spring 2' and rotating the trip shaft 7 by means of the crank 7 so that the trip arm h is moved into its safety position shown in dotted lines, in which position the trip lever on the train passes over without engaging the trip arm h.-

For the purpose of the present invention I arrange a rotary switch contactZ on the trip shaft 9 in such a manner that in the safety position of the trip arm h the moving contact Z connects two fixed spring contacts m, n. as shown in. dotted lines. these contact springs being insulated from the ad jacent parts and connected in a circuit comprising leads 0, 7) leading to an electrically controlled signal, for example, which thus can only be moved to indicate safety when the trip it is in its safety position. The switch parts Z, 927., and n are preferably protected from the weather by a cover q.

Referring now to Fig. 1 of the drawings, a section of a single track railway is shown consisting oftrack rails 1, 2, each end of the section terminating in a station indicated by A at the left hand end and by B at the right hand end, a portion of double track being provided as isusual, at each station to permit of trains travelling in opposite directions passing one another at the station. The single track section between stations A andB is indicated at G. The rails l and 2 of this section are made electrically continuous throughout their length by means of signalling bonds of wire or the like, but the rails must not on any account be cross-bonded as will clearly appear from the description hereinafter given. The rails 1 and 2 of single track section C are insulated from the adjoining portions of double track by the insulation D D at the left hand end andE E at the right hand end of section C.

At the station A trains travelling from left to right are brought to a standstill upon the part of the double track indicated at 3, while at the station B trains travelling from right to left are brought to a standstill on the part of the double track indicated at 4. In the arrangement shewn I provide in proX-' imity to each of the said tracks 3 and 4 a track trip device indicated at 5 (for station A) andti (for station 'B). These track trip devices 5 and 6 may be of any suitable known kind adapted normally to assume the danger position and to remain in that position until .and unless power is positively applied to move the device into another position to allow a train to pass over the same. As shown in the diagram the track trips are supposed to be of the known kind shown in Fig. 3 and described above, the electromagnetic valve admitting fluid under pressure to move trip 5 into safety position being indicated at 7 and. the similar valve for trip 6 being shown at 8. It will of course be understood that with this system a trip lever adapted to coac.t with the track trip device, must be provided upon each train or locomotive requiring to pass along the single track, this lever being arranged to operate a vent valve on a branch pipe extending from the brake pipe of the train or locomotive. In the usual arrangement the trip lever extends vertically downwards, or approximately so, when the vent valve is closed and in case the said lever is moved to an appreciable extent out of this position the vent valve is opened so as to vent the brake pipe and thus apply all. the brakes of the train and locomotive in the usual manner, whether the brakes are of the vacuum or compressed air type. But

it may be made to sound the whistle or may be transmitted to operate a vent valve or signal in the cab'of the engine,-'solong as flthe arrangement is made to elfectivelyf carry out the present purpose, that is, tomake'the stoppage of the train under danger conditions as certain as possible with the minimum of'complication and expense. I

At the station Aa' manually operated controlling switch 9 is provided and at station B a similar controlling switch 10 isprovid'ed. A source of current of a suitably low voltage is provided at each station, being represented in the form of a battery 11 at station A and a battery 12 at station B. It is desirable'that all thecontrolling circuits should normally be open and no current flowing; also it is essential that the two track trips 5 and 6 should normally be in the/danger position, as hereinbefore mentioned, so that a train driven over either trip in this position would be stopped. f

The switch points at station A" should normally be set for the reception of a train approaching from station B, that is, against a train requiring to pass from A to B, :while the switch points at station B' should normally be set for the reception of a train aproachin from station A that is' a ainst a p D 7 7 train requiring to pass from B to A. The starting signals also are normally at danger, the starting signal for controlling a train travelling from A to B'being'shewn at 13 and that for controlling a train'travelling from B to A being shewn at 14. As shown in the diagram the operation of signal 13 is controlled by an electromagnetic device 15 and the operation of the sig'nal'14 is controlled by a similar device 16. I

Each'of the controlling switches 9 and 10 is adapted, when released by the signalman, to automatically return to the vertical position in which each is shown in the diagram and in which all thecircuits controlled by the switches are open. This may be accomplished by any suitable means, for example by means of the weights 17 ,18 secured to the respective switch spindles by arms 19,20.

Each switch 9 and 10 has two operative positions arranged at about 90 from'one another, that is, each operative position is arranged at an angle of about 45 to one side or the other of the normal verticalpo sition of the switch, The position to the right of the vertical is indicated at I and that to the left of the vertical at H. In position I switch blades 9 connects the three contacts 21, 22, 23 of which" contact 211s connected by a conductor 24 to the positive pole of the battery 11, contact 22is connected bya conductor 25 to the track rail 2, and contact 23 is connected by a conductor 26 to the coil 7 of the air admission valve of track trip 5. In position II switch blade-9 connectsthe two contacts 27, 28, of which 27 is connected by a conductor 29-to the negative pole of the battery 11 andfcontact'28 is connected by a conductor 30 to the line wire 31 which connects the coil 7 of the track trip I coil 8 at blade 10 connects the three contacts 32, 33, I

34, of which contact 32is connected by a conductor 35 to thepositive pole of the battery 12, contact 33 is connected by a conductor 36 to the track rail 2, and contact 34 is connected by a conductor 57 to the coil 30f the air admission valve of the track trip 6. In positionII switch blade 10 connects [the contact 38, 39, of which 38 is connected by a conductor 40 to the negative pole of'the battery 12, 'and'39 is connected by a conductor 41 to the line wire 31.; v In addition to the above described 1 connections of the contacts of switches 9 and 10 the end of rail 1 of track section Cnear the station A is connected by a conductor 42 to the negative pole of battery 11 while the opposite end of rail 1 near the station B is connected by a conductor 43 to the negative pole of battery. 12. I

The diagram also shows auxiliary circuits for controlling the points and signals by means of the track trips. Anelectric switch member44 similar to the member 1 shown'in Fig. 3 is operated by the'track trip5 at station A in such a manner that in'the danger positionof thetrip the switch is open and the switch is closed by the movement of the trip toits safety position. The closing ofthe'switch 44 connects the conductor 26 to a conductor 45 and thence to an electromagnetic lock 46 normally'locking the point lever 47 with the points at station'A in position againsta train moving from A toB, this look being connected to the negative side of battery 11 byboriductOrs '48. and 42. On the lever 47 being unlocked the signalman at A can move the points to pass a train from A to B, whereupon a point-operated switch 49 connects the conductor 45 to a conductor 50. leading to the coil 15 0011- trolling the signal 13,the other end ofthe coil 15 being connected by a conductor to the rail 1 or single track section C and thence by conductor 42 to the negative pole of battery 11.

Thus the points at A can only be moved to pass a train from A to B provided that the switch '44 is closed by the movement ofthe track trip 5 into safety position. and this movement of the trip canonly be effected by the r'novement of switch 9 into position I and the simultaneous movementfof switch 10 at station B into 'positioirIl, that is, awayfrom the position I in which the trip 6 at B is moved to safety.

By dividing the conductor 30 and controlling the circuit therethrough. by the pointoperated switch 49 in the manner shown. it isrendered impossible for the signalmanat A to complete the circuit of the trip coil 8 for operating trip 6- at station E unless the points at A are first correctly .set to receive a train from B.

Similar auxiliary arrangements and. circuits are shown at station B, where thetrip 6 operates a switch 52. which connects the electromagnetic lock; 53 of the-point lever 54 to the positive pole. of battery 12. by means of a conductor 55, the coil of lock 53,- being connected to the negative 'pole of the battery by a conductor 56. On the point lever 54 being unlocked by the energizing of. the lock 53 the signahnan at B canmove over the points to start a train from. track 4 at stationB towards A, and on the, points being so moved the point-operated switch 57 connects the operating coil 16 of signal 14 through a divided conductor 58 to the trip switch 52 and thence through switch when in its position I) to the positive pole of battery 12, the coil 16 being connected to the negative pole of the battery through conductors 59 and 43. The conductor 41 connecting the contact 39 of switch. 10 to-theline wire 31 is divided as shown and the circuit 'therethrough iscontrolled by the point-operated switch 57 in a manner and for a purpose similar to that described above with reference to the corresponding circuits at station A. i

In the operation of this system of control, supposing that a train is waiting on track 3 at station A to proceed'to station. B, the signalman. at A communicates with thesignalman at B in the usual manner, for example by telephone or by pro-arranged bell signals, and they both agree to pass the train from A to B. The signalman at A then turns his switch 9 into its position I and the Signalman at B turns his switch 10 into its position II, at the same time making sure that his points are in position to receive the train from A. A current then flows from battery 11 through conductor 24, contact 21, switch blade 9, contact 23, conductor 26, to the electromagnetic valve 7 thence by line wire 31, conductor 41 and point-opei'ated switch 57 to contact 39 of switch 10- position. This movement of the trip closes the switch 44 thereby supplying a current to the lock 46 of point lever 47 enabling the atingv coil of signal 13 is completed, the.

signal drops to saltetyv position, and the train starts unimpeded by the trip 5. With the arrangement illustrated the signalmen at A and B must continue to hold their-respective switches 9 and 10 closed (in posi-v tions I and II respectively) until the cab of the engine has passed the signal 13, as the safety position of the signal is dependent upon. the trip 5 reniaining in safety po sition. Thus the signal 13 should be so locatedrelatively to the insulation D D near the ends of the track rails 1 and. 2 that the cab of the engine can pass the signal before the front wheels of the engine pass on to the rails land 2.. This being the case, as soon as he sees the enginehas passed signal 13 the Signalman at A can release his switch 9 which then; swings into open position under the action of the weight 17 causing the trip 5 and signal 13to return to their normal or danger positions.

Sufiicient indications can be given to the signalmen at A and B as to what is going on by providing any ordinary small type of ammeter in each of the leads'24' and 29 at station A and in-the leads and at station B, as shown in dotted lines in the diagram at 60, 61, 62. and 63 respectively.

In the operation above described, foreX- ample, the current energizing the trip coil 7 at stat-ionA will pass through theammeter 63 in lead 40 at station 13. As soon therefore as the signalman at A releases his switch 9 and this opens as described above the ammeter 63 will swing to zero and indicate this tothe Signalman at B who thereupon will also release his switch 10. The ammeter will indicate to the Signalman at A, firstly, thathis trip coil 7 is energized, secondly, that the trip 5 has moved and switch 44 has closed the circuit through the lock 46 of level 47, thirdly, (after moving over the points inthe manner abovementioned) that the switch 49 has closed the signal circuit, and fourthly, that the battery 11 is short circuited by the leading wheels of the train entering upon tracksection C.

If the signalman at A retains switch 9 closed until the train enters upon single track section C his battery 11 will be short circuited and the trip coil 7, look 46, andsignal coil 15 will all be simultaneously deprived of current, thus causing the trip 5 and signal 13 to return to danger position. This also will be indicated to the Signalman at B by the ammeter 63 swinging to zero, as practically nocurrent will then pass through thecoil 7 and line wire-31.

From the abovedescription' it will be'seen that, with the arrangement showmthe elecfeet in the bonding of the said rail prevent-s the closure of the operating circuit for passing a train in either direction. In order to test the electrical continuity of rail 2 an extremely simple manipulation is all that is.

necessary and may be carried out by each signalman either at stated intervals, or on each occasion when at-rain is received from the opposite end of the section, as follows. On the Signalman at B, for example, seeing his ammeter 63 swing to zero, either when switch 9 opens at station A or when .the approaching train enters the track section C at A with switch 9 still closed, as described just above, he then swings his switch 10 oven from position II into position I for a.

moment. This closes a short circuit from. battery 12 through contacts 32, 33, wire 36, the whole length of rail 2, wheels and axles. of the train just entering track 0 atA, the full length of rail 1 and wire 43 back to battery 12. If rail 2 is electrically continuous Bs ammeter 62 will be traversed 'by a short circuit current and will at once inclicate the fact to the signalman at B who then allows his switch 10 to return to its neutral position. Similarly, the Signalman at A can test for the electrical continuity of rail 2 whenever a train is approaching from B,

by momentarily moving over his switch 9 from position II to position. I when the train is just e'ntering the section C at B. Hence it is not considered essential to provide any additional means for indicating the proper continuity of the bonding of the track rails with this system. Butany known means, such for instance as a continuously energized electromagnet connected in series with rail 2 across a source of current, and )perating an indicating device, may of course be employed for this purpose without. in any way departing from the'present invention.

Thus it will be seen that as long asany part of a train or locomotive is upon' the.

single track C neither the trip 5 at A nor the trip 6 at B can be brought into safety position, so that any train attempting to leave side track 3 at station A or side track 4 at station B under these circumstances will be brought to a standstill. U v I The operation of passing a train from B to A under safety conditions is similar to that described above for. the reverse movement; but in this case the signalmanat B mustniove his switch 10 into its position I and the Signalman at A must move his switch 9 into its position II. The circuits can easily be traced from the diagram, starting from the positive pole of the battery 12 at station B.

It is not necessary to electrically interlock the points and the signal with the trip at 7 each station in the manner shown as in case train actually started from A towards B it would certainly be stopped by the trip 5 ,the

operating circuit of which is open. The, startin signal however will usually be interlocked with the points in accordance with common practice. In this case the signalman A at A could only lower his signal 13 to safety 0y first .moving his points into the corresponding position for a train to pass from side track 3 at A towards station B1 and this movement of the points at A would open the line circuit to coil 8 of trip 6 and thus.

prevent the movement of the trip 6.at B

into safety position, so that neither thetrain from B to A nor that from A to B could be started. It may be preferable however to electrically interlock the trip at each station with thecorresponding points and starting signal in the manner represented in the dia,

gram. In carrying out the saidarrangement care should be taken that the trip coil 7, look coil 16, and signal coil 15,-have approximately the same resistance in order to prevent these coils from shunting one another.

From the above description considered in conjunction with the diagram shewn in Fig. 1 it will be seen that my improved system of controlling trains ona single track is such as will absolutely prevent two trains from starting in opposite directions from the opposite ends of a section of a single track, this result being obtained mainly by so arranging the signalmans v controlling switches 9 and 10, and the line circuit, that each of the two switches has two definite poe ,sitions and both switches must be moved into one or the other position to release one trip, the said operative positions of the switches for moving one trip being arranged switches 9 and 10 are used to directly mu; 1

1 ate the signals instead of the track trips, For this purpose the lead 26from contact 23 of'switch 9, for example, is taken directly to the electroniagnet 15 controlling theoperation of signal 13. In practice the controlling circuit may lirst be closed through a bell 6A in the stationan'asters oflice to announce that the safety circuit is made, the

station-master bringing the starting signal 13 down to safety position by means. of a closed until the engine has passed the signal.

suitable switch 65 which he would retain i other control of the starting signal. This figure also shows thebonded track rails continued along the side track 3 nearly to the slgnal 13,'tl1e bonded portion terminating at the 'insulation'D, .D to enable the train starting from A to B to gain control immediately after passing the starting'signal.

What I claim and desire to secure by Letters Patent is 1. For controlling the traflic running in' both directions on a single track railway, the combination with a continuous bonded rail of a track section, of a traflic-regulating device at each end of the section, one device regulating the tratlic traveling in one direction and the other device regulating the traflic traveling in the opposite direction, means for normally holding both of said traffic-regulating devices in their danger position, electrically operated controlling means for each traflic-regulating device, a normally open circuit for operating said means comprising a line wire connecting the two traflic-regUlating devices and the bonded track rail, acircuit closer for each circuit, each circuit closer having a normal neutral position and'two operative movements therefrom in different directions, one movement to close part of the operating circuit for the corresponding traflic-regulating device and the other movement to close part of the operating circuit for the other trafficregulating device, to necessitate both circuit closers being moved from their respective normal positions in relatively different directions in order to move one of the two trafiic-regulating devices to its safety position, and to render it impossible to close the safety circuits of both of the said trafiicregulating devices at thesame time.

2. For controlling the traffic in both directions on a single track railway, the combination with a track section having both rails bonded throughout, of a traffic regulating device at each end of the section, one device regulating the traiiic'traveling in one direction and the other device regulating the traffic traveling in the other direction, means for normally holding both of said trafiic-regulating devices in their danger positions, electrically operated means controlling each traflic-regulating device, a normally open circuit for operating said means comprising a line wire connecting the two trafiic-regulating devices and one of the track rails, a circuit closer for each circuit, each circuit closer having a normal neutral position and two operative movements therefrom in difiierent directions, one movement to close part of the controlling circuit for the corresponding trafiic-regulating device and the other movement to close part of the controlling circuit for the other trafiicregulating device, and connections to the track rail to cause either trafiicother device controlling the traiiic entering the section from the opposite direction, means for normally holding both of said train-stopping devices in the danger position, a separate electrically controlled power motor for moving each train-stopping device to its safety position, a normally open circuit for controlling each motor, comprising a line Wire and one of the track rails, a circuit closer for each circuit, each circuit closer having a neutral position and two operative movements therefrom in different directions, one movement to close part of the operating circuit for the corresponding train-stopping device, and the other movement to close part of the operating circuit for the othertrain-stoppingdevice, and connections to the othertrack rail controlled by thecircuit closers for preventing the supply of electric current to either one of the said operating circuits as long as any part of a vehicle is in contact with the track section.

4. For the control of traffic on single track railways, the combination with a single tracksection and asignalling station at-each end of the same, of electrically continuous rails of the single track section, one rail being identified herein as the positive and the other as the negativerail, a track device at each station regulating the passage of traffic from the station on to the single track section, an electromagnet at each station controlling the operation of the corresponding track device, a line wire directly connecting the current-exit ends of the coils of the electromagnetsat the two stations, a source of current at each station, a connection from the negative side of each said source to the negative track rail, a manually-actuatedcircuit closer at each station having a normal neutral vposition and two operative positions, and two alternative sets of contacts adapted to be bridged by the circuit closer, accordingv to the operative position to which it is moved, one set for directly connecting the local source of current to the electromagnet at the same station and to the positive track rail, and the alternative set of contacts for connecting the line wire to the negative track rail.

5. For electrically controlling the traflic on single track railways, the combination with a single track section and a signalling station at each end of the same, oi electrically continuous rails of the single track section, a traific-regulating track device, a coil controlling the same and a source of current at each station, a line Wire connecting the said coils at the two stations, a circuit-controlling switch at each station comprising a manually operated member having a neutral position and two operative positions on opposite sides of the neutral position, means acting onthe manually operated member tending to move it to, and retain it in, its neutral position, three separate contacts adapted to be bridged by the manually operated member in one operative position of the same, one contact being connected to the trafic-regulating coil at the same station, the second contact connected to one pole of the source of current at the same stat-ion and the third contact connect ed to one rail of the track, and at least two contacts adapted to be bridged by the moving member in the other operative position of the same, one of these contacts being connccted to the line Wire and the other contact directly connected to the other pole of the said source of current and to the other track rail.

In testimony whereof I have signed my name to this specification.

WALTER JOHN UNDERVVOOD. 

